I consider it one of the unique constraints of the form.
Of course, in this instance, there was an inviting space for it. As laws go, 90 days to come and preserve the art is pretty reasonable to the property owner, but I can also see that given the unique form, he assumed it could be destroyed.
I'm with you... the ephemeral quality of graffiti is a defining attribute. Without that, it's not graffiti any more. Not sure that invalidates the legal argument - it could still be art.
Thinking locally... there's a ton of redevelopment in my area (Reston, VA). If I were a NIMBY, could I doodle on a few walls, throw paper at the courthouse, and bring it all to a stop?
Well, you could make arrangements with the owner to cut the section of the wall. I think some Banksi works have already been sold like that.
Assuming you want to keep art on both side of the wall: attach some sort of steel support to one side of the wall, then cut out the section with a concrete saw, I've seen blade diameters go up to four feet. You'd just need to have the blade on rails.
Why should any public artist have an expectation of their art being preserved? Just because a property owner grants permission, I would assume that property owner reserves the right to change their mind at any time, no?
If it was a sculpture in the parking lot, would we feel the same way? Can the property owner demolish that without the 90 day heads-up?
Can previous artists at that site turn around and sue the last wave of artists for doing the exact same thing?